package com.aiiju.core.util;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.InputStream;

public class FileCodeUtils {
	/**
     * 判断文件的编码格式
     * @param fileName :file
     * @return 文件编码格式
     * @throws Exception
     */
    public static String codeString(String fileName) throws Exception{
        BufferedInputStream bin = new BufferedInputStream(new FileInputStream(fileName));
        int p = (bin.read() << 8) + bin.read();
        String code = null;
        //其中的 0xefbb、0xfffe、0xfeff、0x5c75这些都是这个文件的前面两个字节的16进制数
        switch (p) {
            case 0xefbb:
                code = "UTF-8";
                break;
            case 0xfffe:
                code = "Unicode";
                break;
            case 0xfeff:
                code = "UTF-16BE";
                break;
            case 0x5c75:
                code = "ANSI|ASCII" ;
                break ;
            default:
                code = "GBK";
        }
        
        bin.close();
         
        return code;
    }
    /**
     * 判断文件的编码格式
     * @param fileName :file
     * @return 文件编码格式
     * @throws Exception
     */
    public static String codeString(InputStream inputStream) throws Exception{
    	BufferedInputStream bin = new BufferedInputStream(inputStream);
    	int p = (bin.read() << 8) + bin.read();
    	String code = null;
    	//其中的 0xefbb、0xfffe、0xfeff、0x5c75这些都是这个文件的前面两个字节的16进制数
    	switch (p) {
    	case 0xefbb:
    		code = "UTF-8";
    		break;
    	case 0xfffe:
    		code = "Unicode";
    		break;
    	case 0xfeff:
    		code = "UTF-16BE";
    		break;
    	case 0x5c75:
    		code = "ANSI|ASCII" ;
    		break ;
    	default:
    		code = "GBK";
    	}
    	
    	return code;
    }

}
